As is known, and referring now to FIG. 1, a rights management (RM) and enforcement system is highly desirable in connection with digital content 12 such as digital audio, digital video, digital text, digital data, digital multimedia, etc., where such digital content 12 is to be distributed to users. Upon being received by the user, such user renders or ‘plays’ the digital content with the aid of an appropriate rendering device such as a media player on a personal computer, a portable playback device, or other user computing device 14.
Typically, a content owner distributing such digital content 12 wishes to restrict what the user may do with such distributed digital content 12. For example, the content owner may wish to restrict the user from copying and re-distributing such content 12 to a second user, or may wish to allow distributed digital content 12 to be played only a limited number of times, only for a certain total time, only on a certain type of machine, only on a certain type of media player, only by a certain type of user, etc.
However, after distribution has occurred, such content owner has very little if any control over the digital content 12. An RM system 10 allows the controlled rendering or playing of arbitrary forms of digital content 12, where such control is flexible and definable by the content owner of such digital content. Typically, content 12 is distributed to the user in the form of a package 13 by way of any appropriate distribution channel. The digital content package 13 as distributed may include the digital content 12 encrypted with a symmetric encryption/decryption key (KD), (e.g., (KD(CONTENT))), as well as other information identifying the content, how to acquire a license for such content, etc.
The trust-based RM system 10 allows an owner of digital content 12 to specify rules to be satisfied before such digital content 12 is allowed to be rendered. Such rules may include those aforementioned and/or others, and may be embodied within a digital license 16 that the user/user's computing device 14 (hereinafter, such terms are interchangeable unless circumstances demand otherwise) obtains from the content owner or an agent thereof, or such rules may already be attached to the content 12. Such license 16 may for example include the decryption key (KD) for decrypting the digital content 12, perhaps encrypted according to another key decryptable by the user's computing device or other playback device.
The content owner for a piece of digital content 12 would prefer not to distribute the content 12 to the user unless such owner trusts that the user will abide by the rules specified by such content owner in the license 16 or elsewhere. The user's computing device 14 or other playback device is provided with a trusted component or mechanism 18 that will not render the digital content 12 except according to such rules.
The trusted component 18 typically has an evaluator 20 that reviews the rules, and determines based on the reviewed rules whether the requesting user has the right to render the requested digital content 12 in the manner sought, among other things. As should be understood, the evaluator 20 is trusted in the RM system 10 to carry out the wishes of the owner of the digital content 12 according to the rules, and the user should not be able to easily alter such trusted component 18 and/or the evaluator 20 for any purpose, nefarious or otherwise.
As should be understood, the rules for rendering the content 12 specify whether the user has rights to so render based on any of several factors, including who the user is, where the user is located, what type of computing device 14 or other playback device the user is using, what rendering application is calling the RM system 10, the date, the time, etc. In addition, the rules may limit rendering to a pre-determined number of plays, or pre-determined play time, for example.
The rules may be specified according to any appropriate language and syntax. For example, the language may simply specify attributes and values to be satisfied (e.g., a DATE later than X), or may specify the performance of functions according to a specified script (e.g., IF DATE greater than X, THEN DO Y).
Upon the evaluator 20 determining that the user satisfies the rules, the digital content 12 is rendered. In particular, to render the content 12, the decryption key (KD) is obtained from a pre-defined source and is applied to (KD(CONTENT)) from the content package 13 to result in the actual content 12, and the actual content 12 is in fact rendered.
In an RM system 10, content 12 is packaged for use by a user by encrypting such content 12 and associating a set of rules with the content 12, whereby the content 12 is renderable only in accordance with the rules. Because the content 12 is only rendered in accordance with the rules, the content 12 may be freely distributed. Significantly, the content 12, the rules, and an encrypted version of the decryption key (KD) are communicated to the computing device 14 or other playback device. Moreover, in preparing at least the encrypted version of the decryption key (KD), it would be useful to tie the decryption key (KD) to an object in such a manner that the encrypted version of the decryption key may not be accessed to decrypt and render the content 12 except in the presence of such object. Thus, the content 12, the rules, and the encrypted version of the decryption key (KD) may not be redistributed in a manner so that the content 12 may be rendered widely and in contravention to the wishes of the content owner. As may be appreciated, such object to which the encrypted decryption key (KD) is tied to may be a computing device 14 or other playback device or may be a storage medium such as a disk drive, an optical or magnetic storage disk, or the like.
Accordingly, a copy protection system for personal computers, consumer electronic devices, and other computing devices that is secure, simple, lightweight, and affordable is desired to address one or more of these and other disadvantages.